In large farms it is known to be a common trouble that the soil is compacted by the treads of large farming machines or deteriorated through abuse of chemical fertilizers, the result being deterioration of quality and/or yield of crops.
For improvement of such compacted or deteriorated soil there is known a method in which pores are created in the soil by explosive blasting of air therein through a spike pipe driven in to proper depths. For this new made of ploughing an automotive aerator is used, this being a farm tractor or the like equipped with an aerator or the above-mentioned spike pipe.
Hitherto, ploughing with such an automotive aerator has been made in the following way.
The operator drives a tractor or the like to bring the aerator to where air ploughing is required. There he lower the aerator to a proper height above the ground, and then start a spiking means for driving in the spike pipe to a proper depth in the soil and then, after stopping the spiking means, compressed air is let explosively out into the soil through the spike pipe and nozzle holes at the tip thereof. In this conventional manner, the operator judges with his skill whether the height of the holding frame or aerator, the depth of the spike pipe under the ground are proper. Therefore, the spike pipe is not accurately driven into the soil by the predetermined depth. Consequently, the ploughing is not even locally, and the state of the crop is not so good as expected.
And it was not seldom that the tractor is moved before the spike pipe had been drawn out of the ground. In such case, the spiking pipe is bent or broken off.
In some case, more than two spike pipes are equipped on one tractor for the improvement of aeration efficiency. In such cases it is desirable to make the distance between the individual spike pipes adjustable for proper aeration to be made according to the planting interval of fruit trees, ridge width, soil hardness, degree of soil deterioration etc.